FIELD: electric drives of machine tools. SUBSTANCE: during starting period, motor phase windings are connected in open delta. First winding (delta base) is connected to single-phase line while second and third windings are connected in parallel with running capacitor and phase-shifting unit, respectively, the latter being made in the form of naturally switched-over thyristor switch with delayed turn-on respect to moment of voltage zero crossing its terminal leads. During running period, windings are connected in delta with capacitor inserted between top and one of base terminals. Starting capacitor is not required. EFFECT: provision for dispensing with starting capacitor. 3 dwg
